Synthesis of tetranuclear dyes

ABSTRACT

TETRANUCLEAR DYES DERIVED FROM A 2-IMIDAZOLIN-4-ONE, A 2-IMIDAZOLIN-4-THIONE AND A 2-IMIDAZOLIN-4-SELENONE ARE PREPARED IN GOOD YIELDS BY CONDENSING A QUATERNIZED MEROCYANINE DYE DERIVED FROM A 2-IMIDAZOLIN-4-ONE, A 2-IMIDAZOLIN-4-THIONE OR A 2-IMIDAZOLIN4-SELENONE WITH (1) A DIALKOXYALKYL ESTER OF AN ORGANIC ACID, (2) A TRIALKOXY ALKANE OR ARYL COMPOUND, (3) A 3,3-DIALKOZY-1ALKOXYPROPENE, (4) A 1-ANILINO-5-PHENYLIMINO-1,3-PENTADIENE OR (5) A SECOND QUATERNIZED MROCYANINE DYE DERIVED FROM A 2-IMIDAZOLIN-4-ONE, A 2-IMIDAZOLIN-4THIONE OR A 2-IMIDAZOLIN-4-SELENONE, EACH HAVING SUBSTITUTED ON THE CARBON IN THE 2-POSITION A GROUP SUCH AS A B-ACETANILIDOVINYL GROUP, A 4-ACETANILIDO-1,3-BUTADIENYL GROUP, AND A 6-ACETANILIDO-1,3,5-HEXADIENYL GROUP.

United States Patent M ABSTRACT THE DISCLOSURE Tetranuclear dyes derivedfrom a 2-imidazolin-4-one,

a 2-imidazolin-4-thione and a 2-imidazolin- 4-selenone are prepared ingood ,yields bycondensing a quaternized merocyanine dye derived from a2-imidazolin-4-one, a

2-imidazolin-4-thione or a 2-imidazolir1-4-selenone with t (1) adialkoxyal-kyl ester of an organic acid, (2) a trialkoxy alkane or arylcompound, (3) a 3,3-dialkoxy-1- alkoxypropene, (4) a 1-anilino-5pheny1imino-1,3-pentadiene or (5) a second quaternized merocyanine dyederived from a 2-imidazolin-4-one, a 2-imidazolin-4- thione ora2-imidazolin-4 selenone, each having substituted on the carbon in the2-position a group such as a fl-acetanilidovinyl group, a4-acetanilido-1,3-butadienyl group, and a G-acetanilido-1,3,5-hexadienylgroup.

This invention relates to 'certain tetranuclear cyanine dyes forsensitizing photographic emulsions and particularly to the synthesis ofthese dyes.

It is known to use certain cyanine dyes as spectral sensitizing dyes inphotographic silver halide emulsion layers. It is also known to usecertain complex dyes such as thejdyes of Heseltine et al. US. Pat.2,927,026, issued Mar. 1, 1960, and of :French Pat. 994,762'as spectralsensitizing dyes. The synthesis of tetrauuclear irnidazolino cyaninedyes described in French Pat. 994,762 gives low yields. New syntheticmethods are needed for the preparation in good yields of tetranuclearimidazolino cyanine dyes. i

chlorobenzothiazole, 4-methylbenzothiazo1e,

3,558,614 Patented Jan. 26, 1971 D each represent an atom selected fromthe class consisting of oxygen, sulfur and selenium; X represents ananion (e.g., bromide, iodide, chloride, methyl sulfate, ethyl sulfate,methyl sulfonate, phenyl sulfonate, ptoluene sulfonate, perchlorate,etc.) d and q each represents the same or different integer of from 1 to2; n, m and p each represent the same or dilferent integer from 1 to 3;L represents a methine group (e.g., CE-- where E represents hydrogen, alower alkyl group, such as methyl, ethyl, butyl, etc., and an arylgroup, such as phenyl, tolyl, naphthyl, etc., such that not more thanone L group per conjugated chain contains an E group that is other thanhydrogen); and Z and Z each represents the same or different nonmetallicatoms required to complete a basic heterocyclic nucleus having from 5-to 6-atoms inthe heterocyclic ring, including such heterocyclic nucleias the thiazole nucleus (e.g., thiazole, 4-methylthiazole,4-phenylthiazole, 5-methylthiazole, 4,5- dimethylthiazole,4,5-diphenylthiaz0le, etc.), a benzothiazole nucleus (e.g.,benzothiazole, 4-chlorobenzothiazole, S-chlorobenzothiazole,6-chlor0benzothiazole, 7- 6-methy1- benzothiazole, 5-bromobenzothiazole,5-methoxybenzothiazole, 6-iodobenzothiazo1e,5,6-dirnethoxybe'nzothiazole, etc.), a naphthothiazole nucleus (e.g.,a-naphthol thiazole, fl-naphthothiazole, S-methoxy-fi-naphthothiazole,

, oxazole, 4,5-diphenyloxazole,

8-ethoxy-a-naphthothiazole, ap-naphthothiazole, etc.), athianaphtheno-7',6,4,S-thiazole nucleus (e.g.,4-methoxythianaphtheno-7',6',4,5-thiazole, etc.), an oxazole nucleus(e.g., 4-methyloxazo1e, 5-methyloxazole, 4-phenyl- 4-ethyloxazole,4,5-dimethyloxazole, etc.), a benzoxazole nucleus (e.g., benz- It istherefore an object of my invention to provide a valuable, novelsynthesis for tetranuclear dyes derived from a 2-imidaz01in-4-one, a2-irnidazolin-4-thione, and a 2-imidazolin-4-selenone. Another object isto provide a novel method forsynthesizing in good yields tetranucleardyes derived from a 2-imidazolin-4-one, a 2- imidazolin-4-thione, and aZ-imidazolin 4 selenone. Another object is to provide valuabletetranuclear cyanine dyes for use in sensitizing photographic materials.Still other objects will become evident from the following specificationand, claims.

These and other objects are accomplished according to my invention bythe synthesis and use of my tetranuclear cyanine dyes including thoserepresented byjthe formula:

I. D R5 11 l X Z A t R5 D1 15 b oxazole, S-chlorobenzoxazole,S-methylbenzoxazole, 5- phenylbenzoxazole, 6-methylbenzoxazole,5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, S-ethoxy'benzoxazole,5,6-dichlorobenzoxazole, S-hydroxybenzoxazole, etc.), a naphthoxazolenucleus (e.g., a-naphthoxazole, fl-naphthoxazole, 13,;8-naphthoxazole,etc.), a selenazole nucleus (e.g., 4-methylselenazole,4-phenylselena'zole, etc.), a benzoselenaz'ole nucleus (e.g.,benzoselenazole, 5-chlorobenzoselenazole, S-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.) anaphthoselenazole; (e.g., a-naphthoselenazole, naphthoselenazole,5,,3-naphthoselenazole, etc.), a thiazoline nucleus (e.g., thiazoline,4-methylthiazoline, etc.), a pyridine nucleus ,(e.g., 2--pyridine,4-pyridine, S-methyl-Z-pyridine, 3-methyl-4-pyridine, etc.), a quinolinenucleus (e.g., Z-quinoline, 4-quinoli-ne, 3 rnethyl-2- quinoline,5-ethyl-2-quino1ine, 6-chloro-2-quinoline, 8- ch1oro-2-quin0line,4-methoxy-2-quinoline, 8-hydroxy-2- quinoline, 6-methoxy-4-quino1ine,7-methyl-4-quinoline,

8-chloro-4-quinoline, etc.), an isoquinoline nucleus (e.g.,Lisoquinoline, 3-isoquinoline, 3-4-dihydro-1-isoquinoline, etc.), a3,3-dialkylindolenine nucleus (e.g.,

3,3-dimethylindolenine, 3,3,5-trimethylindolenine, 3,3,7 trimethylindolenine, etc.), an imidazole nucleus (e.g., l-allylimidazole,l-alkylimidazole, l-alkyl-4-phenylimidazole, 1-alkyl-4,5dimethylimidazole, etc.), a benzimidazole nucleus (e.g.,l-allyl-benzimidazole, l-alkylbenzimidazole,1-aryl-5,G-dichlorobenzimidazole, etc.), a naphthimidazole nucleus(e.g., 1-alkyl-m-naphthimidazole, l-aryl-fi-naphthimidazole,1-alkyl-S-methoxy-fi-naphthirnidazole, etc.).

According to my invention dyes of Formula I are prepared by acondensation reaction in a mixture of a first compound having theformula:

wherein R R R Z, d, L, n, D and X are as defined previously, and asecond compound having one of the formulas:

wherein R and R each represent the same or a different group, e.g.,lower alkyl (e.g., methyl, ethyl, propyl, etc.), lower alkoxy (e.g.,methoxy, ethoxy, propoxy, etc.).

wherein R R R Z L, D X q, p and mare as defined previously; R representsan aryl group such as a phenyl group (e.g., phenyl, tolyl, ethylphenyl,etc.); and R represents hydrogen or an acyl group (e.g., acetyl,propionyl, benzoyl, etc.). The condensation reaction mixture isadvantageously heated, preferably in an inert organic solvent andpreferably in the presence of an acid acceptor. The condensationreaction is accelerated by heating in the range from room temperature tothe reflux temperature of the reaction mixture. Any of the inert organicsolvents usually used in cyanine dye-forming condensation reactions areused to advantage, including pyridine, quinoline, benzene, toluene,nitrobenzene, ethanol,

propanol, butanol, N,N-dimethylacetamide, etc. Any of the acid acceptors(basic condensing agents) usually used in cyanine dye-formingcondensation reactions are used to advantage including pyridine, atrialkylamine (e.g., triethylamine, tripropylamine, triisopropylamine,tributylamine, triisobutylamine, triamylamine, etc.), anN-alkylpiperidine (e.g., N methylpiperidine, N-ethylpiperidine, etc.),an N,N-dialkylaniline (e.g., N,N dimethylaniline, N,N-diethylaniline,etc.), etc.

Dyes of Formula I in which m is the integer 1, 2 and 3 areadvantageously made by using in the condensation reaction as the secondcompound an intermediate of Formula III (or IV), V, and VI,respectively. A second compound of Formula VII is advantageously used inmy condensation reaction with a dye of Formula II to make unsymmetricaldyes of Formula I.

The dyes of Formula II are well known and have been described inreferences, such as German Pat. 8052, issued Jan. 17, 1955, German Pat.9740, issued May 2, 1955, Heseltine and Brooker US. Pat. 2,927,026,issued May 1, 1960. The dyes of Formula II in which D represents sulfurare derived from the appropriate 2-imidazolin 4- thione in place of the2-imidazolin-4-one. The dyes of Formula II in which D representsselenium are prepared from the corresponding dye in which D representssulfur by a method similar to that described in US. Pat. 2,- 322,433 byfirst treating with an alkyl salt (ester), to quaternize the acidicnucleus and then treating the quaternary salt formed (dissolved in asuitable solvent) with an alkali metal selenide, such as sodiumselenide.

The intermediates of Formulas III, IV, V, and VI are known in the art,and those that are not readily available can be prepared by methodsknown to those skilled in the art.

The compounds of Formula VII are prepared to advantage by heating a dyeof Formula II with the appropriate intermediate, such as, ethylisoformanilide (for compounds of Formula VII where m is the integer 1),anilinoacrolein anil hydrochloride (for compounds of Formula VII where mis the integer 2) and glutaconicaldehydedianilide hydrochloride (forcompounds of Formula VII where m is the integer 3) and subsequentlytreating with acetic anhydride, propionic anhydride, benzoyl chloride,etc. to replace the hydrogen on the nitrogen atom with an acyl group (RThese condensation reactions used to make compounds of Formula VI areadvantageously carried out in any of the previously mentioned inertorganic solvents used in the cyanine dye-forming condensation reactions.It is advantageous to heat the reaction mixture to a temperature betweenroom temperature and the reflux temperature for the mixture.

The invention is further illustrated by the following examples which,however, are not to be construed as limiting the invention.

EXAMPLE 1 3,3 diethyl 5,5'-di(3-ethyI-Z-benzothiazolinylidene)- 4,4dioxo 1,1 diphenylimidazolinocarbocyanine perchlorate (J2EE Into areaction flask is placed 15 ml. of pyridine, 2.35 g. (1 mol.) of3-ethyl-5-(3-ethyl-2-benzothiazolinylidene)-2-methyl-4-oxo-1-phenyl-2-imidazolinium perchlorate, 2.5 g. ofdiethoxymethyl acetate and 0.25 g. (1 mol.) of triethylamine. Theresulting solution is heated under reflux for ten minutes. On coolingml. of water is added. The mixture is chilled for a period of twelvehours and the water is decanted. The residual oil is boiled with 15 ml.of methanol; The solution is chilled and the precipitated productcollected by filtration, washed with methanol and dried. This product isrecrystallized twice from boiling N,N-dimethylformamide and methanol.The resulting dye (M.P. 291.5292.5 C., dec.) corresponding to the aboveindicated formula is obtained in a good yield.

3,558,614 S 6 I .EXAMPLE 2 phenyl [1,3,3 trimet hyl -2indolinylidene)etl1yl- I th th a 1dene]-2-1m1dazol1n1um 1od1de as theintermedlate in place w fia g} d g i igfif i g i ggi of3-ethyl-5-[(3-ethyl-2-benzoxazolmylidene)ethyl1dene1- j b ocyanine iodide Into a reaction flask is placed 15 ml. of pyridine, 2.5 g.2-methyl-4-0Xo-l-phenyl-Z-imidazolinium iodide. A good (1 mol.) er 3ethyl 5-[3-ethyl-2-benzoxazolinylidene) yield of pure dye, M.P.300.0301.'l) C. dec. is obtained. ethylidene] 2methyl-4-oxo-l-phenyl-Z-imidazolinium V EXAMPLE 6 iodide, and 2.0 g. ofdiethoxymethyl acetate. The resulting solution is heated under refluxfor fifteen minutes. The lm P lienzothlflolmylldene) reaction mixture isthen cooled and diluted with water. ethylldefnel dloxo'Ll'dlphenyhmldazohnocar The resulting suspension is chilled for a periodof about bocyamne lodldetwelve hours and the crude product is collectedby filtra- Dye is prepared by a method similar to that described tionand dried. This crude product is boiled with 50' ml. for Dye 2 inExample 2 using 3-ethy1-5-[(3-ethyl-2- of methanol. After chilling, themixture is filtered and the benzothiazolinylidene)ethylidene] 2methyl-4-oxo-1- precipitate is washed with methanol and dried. After onephenyl-Z-imidazolinium iodide as the intermediate in placerecrystallizationfrom pyridine and methanol followed by of3-ethyl-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene]- recrystallizationfrom methanol alone, theyield of pure 2 methyl4-oXo-1-phenyl-2-irnidazolinium iodide. The dye, M.P. 242.0 to 244.0" C.dec., having the above indiyield of pure dye is 31%, M.P. 254.0256.0 C.dec. cated structure, is 297 I; AMPL 3 EXAMPLE 7 v M e X E5,5-'di[(3,3-dimethyl 1 a sulfobutyl-lH-benz(e)- 1,1,3,3 tetraethyl 4,4di0Xo-5,5'-di[(l,3,3-trimethyl indolin 2ylidene)ethylidene]-3,3-diethyl-4,4-di0xo- 2indolinylidene)ethylidene]imidazolinocarbocyanine1,l'-diphenylimidazolinocarbocyanine iodide disodium iodide salt.

on. CH3 on, on, I 0 OzH 02135 O.

C H I 0 /CN\ /N-C\ C=CH-CH-:O\ /C=CHGH=CHG/ C=CH-CH=C e l N e CH3 C2115C2H5 (3H3 l I Intoa reaction flask is placed 10ml. of pyridine, 2.3 Dye7 i r d b a th d i il to h t d g. (1 mol.) of1,3*diethyl-Z-methyl-4-oxo-5-[(l,3,3,-triscribed for Dye 2 in Example 2using 5-[(3,3-dimethylmethyl 2 indolinylidene)ethylidene]Z-imidazolinium 1-6-sulfobutyl -1H-benz(e)indolin-Z-ylidene)ethylidene]- iodide and 2.5 g. ofdiethoxymethyl acetate. The resulting 3-ethyl-4-oxo-1-phenyl-2imidazolinium iodide sodium solution is heated under reflux for twentyminutes. The r salt as the intermediate in place of3-ethyl-5-[(3-ethyl-2- mixture iscooled and diluted with 200 ml. ofwater. The benzoxazolinylidene)ethylidene1-2-methyl 4 oxo 1- mixture ischilled overnight. The Water is decanted and henyI-Z-imidaZ Iiniumiodide. The pure dye has an M.P.

the residual gum is air dried. After crystallization from indefi it decresol and methanol followed by one recrystallization EXAMPLE 3:

from the same solvents the dye of the above indicated fori mula, M.P.269.5 to 270.5" c. dec., is obtained. 3,3 t 5,5 Q 3 r -e y1dene-)ethyl1dene] 4,4 dioxolmidazollnocarbocyanlne EXAMPLE 4 iodide.3,3'-diethyl5,5-di( 1-ethy1n p h0[ dlthialolin Dye 8 is prepared by amethod similar to that described yl f d p t y m y for Dye 3 in Example 3using 1,3-diethyl-5-[(3-ethyl-2- mne perchlorate. ibenzoxazolinylidene)ethylidene] 4oxo-2-imidazolinium DyB 4 is Preparedby a method similar to that lodrde as the mtermediate A good yield ofpure dye is scribed for Dye l in Example 1 using 3-ethyl-5-(1-ethylObtained 2770*2780 naphtho[1,2-d] -thiazolin-2-ylidene)-2-methyl-4 0x01- phenyl-Z-imadazolinirirh perchlorate as the intermediate EXAMPLE 9 inplace of 3-ethyl-5-(3-ethyl-2-benzothiazolinylidene)-2- lflififi'r 'F yl y methyl-4-oxo-l-2-imidazolinium perchlorate. The yield 1 YdiOXOimidaZOlillOcarbocyallifle of pure dye is 41%, M.P. 240.0-241.5 c.dec. Iodide- EXAMPLE 5 Dye 9 is prepared by a method similar to thatdescribed for Dye 3 in Example 3 using 1,3-diethyl-5-[(3-ethyl-2-benzothiazolinylidene)ethylidene] 4 oxo 2 imidazolim'um iodide as theintermediate in place of. 1,3-diethyl-2- methyl-4-oXo-5-1,3,3-trimethyl-2 indolinylidene) ethyli Dye Sis prepared by a methodsimilar to that described idene]-2-imidazolinium iodide. The yield ofpure dye is for Dye 2 in Example 2 using 3-ethyl-2-methyl-4-oxo-1- 29%,M.P. 301.0-302.0'C'. dec.

3,3'-diethyl-4,4f dioxo 1, 1 diphenyl-5,5'-di[(1,3,3-

trimethyl 2 indolinylidene)ethylideneJimidazolinocarbocyanine iodide.

7 EXAMPLE 10 3,3-diethyl 5,5 di[(3 ethyl Z-benzoxazolinylidene)ethylidene] 1,1 diphenyl 4,4 dithioxoimidazolinocarbocyanine iodide.

Dye 10 is advantageously prepared by a method similar to that describedfor Dye 2 but using an equimolar amount of 3-ethyl 5 [(3-ethyl 2benzoxazolinylidene)ethylidene] 2 methyl 1 phenyl 4 thioxo-2-imidazolinium iodide in place of 3 ethyl 5 [(3-ethyl-2-benzoxazolinylidene)ethylidene] 2 methyl 4 oxol-phenyl 2 imidazoliniumiodide. Yields similar to those of Dye 2 (in Example 2) are obtained.

EXAMPLE 11 3,3'diethyl 5,5 di[(3 ethyl 2 benzoxazolinylidene)ethylidene]-1,1,7-triphenyl 4,4 diselenoxoimidazolinocarbocyanineiodide.

Dye 11 is advantageously prepared by a method similar to that describedfor Dye 2 but using an equimolar amount of 3-ethyl 5 [(3-ethy1 2benzoxazolinylidene)ethylidene] 2 methyl 1 phenyl 4 selenoxo-2-imidazolinium iodide in place of 3-ethyl-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene] 2 methyl 4 X0- l-phenyl 2 imidazoliniumiodide and an equimolar amount of ethyl orthobenzoate in place ofdiethoxymethyl acetate. Yields similar to those of Dye 2 (in Example 2)are obtained.

These and other dyes of Formula I (m=1) are advantageously prepared ingood yields by heating mixtures of still other compounds of Formula IIwith other compounds of Formula 111 (e.g., dimethoxymethyl propionate,diethoxymethyl butyrate, etc.) and Formula IV (e.g., ethyl orthoformate,ethyl orthoacetate, ethyl orthobenzoate, etc.).

EXAMPLE 12 3,3-diethyl 5,5 di[(3 ethyl 2 benzoxazolinylidene)ethylidene]4,4 dioxo 1,1 diphenylimidazolinodicarbocyanine iodide.

Dye 12 is advantageously prepared by a method similar to that describedfor Dye 2 in Example 2 but using an equimolar amount oftrimethoxypropene in place of diethoxymethyl acetate.

Similarly, other tetranuclear dicarbocyanine dyes of my invention areadvantageously prepared in good yields by heating other compounds ofFormula II with other compounds of Formula V including, e.g.,triethoxypropene, 3,3 diethoxy 1 methoxypropene, trirnethoxypropene,tripropoxypropene, etc.

EXAMPLE 13 3,3 diethyl 5,5 di[(3 ethyl 2 benzoxazolinylidene)ethylidene]4,4 dioxo 1,1 diphenylimidazolinotricarbocyanine iodide.

Dye 13 is advantageously prepared by a method simi lar to that describedfor Dye 2 in Example 2 but using an equimolar amount of l-anilinophenylimino-1,3- pentadienyl hydrochloride in place of diethoxymethylacetate.

Similarly, other tetranuclear tricarbocyanine dyes of Formula I areadvantageously prepared in good yields by heating other compounds ofFormula II with other compounds of Formula VI, e.g., 1 anilino 5 (4-methylphenylimino) 1,3 pentadiene, 1 (4 methylanilino) 5 phenylimino 1,3pentadiene, 1-(2- methoxyanilino)-5-phenylimino-1,3-pentadiene, etc.

The following will illustrate the synthesis of typical unsymmetricaldyes of my invention. Good yields are obtained.

EXAMPLE 14 3,3 diethyl 5 (3 ethyl 2 benzothiazolinylidene) 5' (3 ethyl 2benzoxazolinylidene)ethylidene] 4,4 dioxo 1,1diphenylimidazolinocarbocyanine iodide.

Dye 14 is prepared by heating equimolar amounts ofZ-(fl-acetanilidovinyl) 3 ethyl 5 (3 ethyl-2- benzothiazolinylidene) 4oxo 1 phenyl 2 imidazolinium perchlorate and 3-ethyl-5-[(3-ethyl 2benzoxazolinylidene)ethylidene] 2 methyl 4 oxo-l-phenyl- Z-imidazoliniumiodide with triethylamine (1 mol and excess) dissolved in pyridine.Following completion of the reaction, the hot mixture is cooled anddiluted with water. The dye suspension is chilled overnight. The crudedye is collected by filtration, washed and purified by the usualprocedures.

EXAMPLE l5 1,3,3 triethyl-5'-(3-ethyl-2-benzothiazolinylidene)-4,4-dioxo 1 phenyl-5-[(1,3,3-trimethyl-2-indolinylidene)ethylidene]-imidazolinocarbocyanine iodide Dye 15 is prepared by heatingequimolar amounts of 2(fi-acetanilidovinyl)-3-ethyl-5-(3-ethyl-2-benzothiazolinylidene)4-oxo-l-phenyl-Z-imidazolinium perchlorate and 1,3diethyl-2-methyl-4-oxo-5-[(1,3,3-trimethyl-2-indolinylidene)ethylidene]-2-imidazoliniurniodide with triethylamine (1 mol.+l00% excess) dissolved. in pyridine.The dye formed is separated and purified by methods similar to thosedescribed previously.

EXAMPLE 16 1,3 diethyl 5 3 -ethyl-2-benzothiazolinylidene -5 (3- ethyl 2benzoxazolinylidene )ethylidene] -4-oxo-1,3-diphenyl-4-thioxoimidazolinocarbocyanine iodide Dye 16 is advantageouslyprepared by heating equimolar amounts of2-(,B-acetanilidovinyl)-1-ethyl-5-(3 ethylZ-benzothiazolinylidene)-4-oxo-3-phenyl-2-imidaz olinium perchlorate and3 ethyl-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene]2-methyl-1-phenyl-4-thioxo-2- imidazolinium iodide with triethylamine (1mol. and

100% excess) dissolved in pyridine. Following. completion of thereaction the hot mixture is diluted with water.

The dye suspension is chilled overnight. The crude dye is collected byfiltration, washed and purified by the usual procedures.

EXAMPLE 17 3,3 diethyl-5-[ 3-ethyl-Z-benzoxazolinylidene)-ethylidene]4,4 dioxo-1,1-diphenyl-5-[(1,3,3trimethyl- 2indolinylidene)ethylidene]imidazolinocarbocyanine iodide Dye 17 isadvantageously prepared by heating equimolar amounts of 2(2-anilinovinyl)-3-ethyl-4-oxo-lphenyl 5[(1,3,3-trimethyl-2-indolinylidene)ethylidene] 2 imidazolinium iodideand 3-ethyl-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene] 2methyl-4-oxo-l-phenyl-2-imidazolinium iodide, acetic anhydride andtriethylamine dissolved in pyridine. Following completion of thereaction, the mixture is cooled and diluted with water. The dyesuspension is chilled over night, and crude dye collected by filtrationand dried giving a yield of 36%. After purification by recrystallizationpure dye having a M.P. 247248 C. dec. is obtained.

EXAMPLE 18 3,3 diethyl 5 [(3-ethyl-2-benzoxazolinylidene)-ethylidene] 5[(1,3,3-trimethyl-2-indolinylidene)ethylidene] 4,4dioxo-1,1'-diphenylimidazolinodicarbocyanine iodide Dye 18 isadvantageously prepared by a method similar to that described for Dye 17(in Example 17) using 2 (4acetanilindo-1,3-butadienyl)-l,3-diethyl-4-oxo-5- [(1,3,3 trimethyl 2indolinylidene)ethylidene]-2-im idazolinium iodide in place of the2-anilinovinyl analog used to make Dye 17. Similarly, goodyields areObtained of the purified dye.

9 EXAMPLE 19 3,3 diethyl [(3-ethyl-Z-benzoxazolinylidene)-ethylidene]4,4 dioxo-l,1 dipheny1-S'-[(1,3,3-trimethyl- 2indolinylidene)ethylidene]-imidazolinotricarbocyanine, iodide EXAMPLE 202 (2anilinovinyl)-3-ethyl-5-(3-ethyl-2-benzothiazolinylidene)-4-oxo-l-phenyl-Z-imidazoliniumperchlorate 3 ethyl 5 (3 ethyl 2 henzothiazolinylidene)-2- methyl-4-oxo-1-phenyl 2 imidazolinium perchlorate (1 mol., 2.35 g.) and ethylisoformanilide (1 mol. +200-%, 2.25 g.) is dissolved inN,N-dimethylacetamide ml.), and the solution is heated under reflux forthirty minutes. The reaction mixture is cooled and diluted with ethylether (350 ml.). After chilling, the ether is decanted and the residualoil is dried in a vacuum oven. The, yield of product is 2.05 g. (72%).This crude dye is employed without further purification as anintermediate in the preparation of my dyes.

The good yields of dye produced by my synthesis represent a valuabletechnical advance over the prior art synthesis. The following comparisonwill illustrate this. Pure,

Dye 2 is prepared in a yield of 29% according to my invention in Example2. Pure Dye 2 is also carefully prepared using the prior art type ofreactions indicated in French Pat. 994,762, however, this synthesisgives only a 1% yield of the pure dye. Similarly other comparisons canbe made to illustrate the technical advance for my synthesis.

My dyes are used to advantage to spectrally sensitize photographicsilver halide emulsions. My photographic emulsions contain any of thesilver halides or mixtures thereof dispersed in any of the hydrophiliccolloids used in photographic emulsions including natural materials,e.g., gelatin, albumin, agar-agar, gum arabic, alginic acid, etc., andsynthetic materials, e.g., polyvinyl alcohol, polyvinyl pyrrolidone,cellulose ethers, partially hydrolyzed cellulose acetate, etc. My dyesare especially useful for extending the spectral sensitivity of thecustomarily employed gelatino-silver-chloride,gelatino-silvenchloroibro- 'rnide, gelatino-silver-bromide, andgelatino-silver-bromoiodide emulsions. To prepare emulsions sensitizedwith one or more of the novel dyes, it is onlynecessary to disperse thedye of dyes in the emulsions. The methods of incorporating dyes inemulsions are simple and are known to those skilled in the art. Inpractice, is is convenient to add the dyes to the emulsions in theformof a solution in an appropriate solvent. A mixture of methyl alcoholand pyridine is advantageously employed as a solvent. The dyes areadvantageously incorporated in the finished, washed emulsions and shouldbe uniformly distributed throughout the emulsions. The particularsolvent used will, of course, depend on the solubility properties of theparticular dye.

The concentration of the dyes in the emulsions can vary widely, e.g.,from 5 to 100mg. per liter of flowable emulsion. The concentration ofthe dyes will vary accord' ing to the'type of emulsion and according tothe effect desired. The suitable and most economical concentration forany given emulsion will be apparent to those skilled in the art, uponmaking the ordinary tests and observations customarily used in the artof emulsion making. To prepare a gelatino-silver-halide emulsionsensitized with one or more of my dyes, the following procedure issatisfactory. i

A quantity of dye is dissolved in'a mixture of methanol and pyridine anda volume of this solution, which may be diluted with water, containingfrom 5 to mg. of dye, is slowly added to about 1000 cc. ofgelatino-silver-halide emulsion, with stirring. Stirring is continueduntil the dye is thoroughly dispersed in the emulsion.

With most of the dyes, from 10 to 20 mg. of dye per liter ofgelatino-silver-bromide or bromoiodide emulsion (containing about 40 g.of silver halide) sufiices to produce the maximum sensitizing effect.With the finer grain emulsions, a somewhat larger concentration of dyemay be needed to produce the maximum sensitizing elfect.

The above statements are only illustrative, as it will be'apparent thatthe dyes can be incorporated in photographic emulsions by any of theother methods, customarily employed in the art, e.g., by bathing a plateor film upon which an emulsion is coated in a solution of the dye in anappropriate solvent. However, bathing methods are ordinarily not to bepreferred. Emulsions sensitized with the dyes can be coated on suitablesupports, such as glass, cellulose derivative film, resin film .or paperin the usual manner.

Photographic silver halide emulsions, such as those listed above,containing the sensitizing dyes of this invention can also contain suchaddenda as chemical sensitizers (e.g., sulfur sensitizers, such as allylthiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), variousgold compounds (such as potassium chloroaurate, auric trichloride, etc.)(see U.S. Pats. 2,540,085; 2,597,856; and 2,597,915, for example),various palladium compounds (such as palladium chloride (U.S. Pat.2,540,086), potassium chloropalladate (U.S. Pat. 2,598,079), etc., ormixtures of such sensitizers), antifoggants (e.g., benzotriazole,nitrobenzimidazole, S-nitroindazole, etc. (see Mees: The Theory of thePhotographic Process, Mac- Millan Pub., 1942, p. 460), or mixturesthereof), hardeners (e.g., formaldehyde (U.S. Pat. 1,763,533), chromealum (U.S. Pat. 1,763,533), glyoxal (German Pat. 538,- 713),dibromacrolein (Great Britain Pat. 406,750), etc.), color couplers(e.g., such as those described in U.S. Pat. 2,423,730, Spence andCarroll U.S. Pat. 2,640,776, issued June 2, 1953, etc.), or mixtures ofsuch addenda. Dispersing agents for color couplers, such assubstantially Water-insoluble, high boiling crystalloidal materials,such as those set forth in U.S. Pats. 2,322,027 and 2,304,940, can alsobe employed in the above-described emulsions.

In the manner described above, :a number of the dyes of this inventionrepresented by Formula I above are separately incorporated in anordinary gelatino-silverchlorobromide emulsion, the dyes being added inthe form of a solutiomThe dyes are then thoroughly incorporated in theemulsions by stirring. After a short digestion, the emulsions are coatedonto ordinary cellulose acetate film supports and the coating exposed ina spectrograph and sensitometer and then developedin Kodak D-l9developer solution and fixed in an alkaline thiosulfate bath. Thesensitizing range and maximum absorption for several typical dyes areindicated in the following table.

Maximum Similarly it can be shown that the other dyes of my inventionare valuable spectral sensitizers for use in photography.

a 'n tetranuclear d My synthesls 1s valuable for prep r1 g @g H C C CHOH dyes of Formula I because of the good yields of the dye product.Prior art synthesis when applied to the R 1 R synthesis of my dye 2 gaveonly a 1% yield compared d to the good yield of 29% of dye 2 made by mysynthesis. Dr d The invention has been described in detail with par-"'ZN 6 R ticular embodiments thereof but it will be understood that l 69ll variations and modifications can be elfected Within the R N(CH=CH);TO(:L*L)E?C /C( OH=CH)N spirit and scope of the invention asdescribed hereinabove I Ru and as defined in the appended claims. claim:wherein R R R Z q, L, p, 111, D and X are as defined previously; R R Rand R each represents a 1. A process for preparing a tetranuclear dyehaving 7 lower alkyl group; R and R each represents a group the formula:

selected from the class consisting of hydrogen, lower alkyl and loweralkoxy; R represents a phenyl group; and R represents a group selectedfrom the class consisting of hydrogen, benzoyl and a lower alkanoylgroup; said reaction being conducted in an organic solvent.

2. A process for preparing a tetranuclear dye having wherein R and Reach represents a group selected from the class consisting of an alkylgroup containing from 1 to 12 carbon atoms and phenyl; R R R and R eachrepresents a group selected from the class consisting of an al'kyl groupcontaining from 1 to 12 carbon atoms and phenyl; D and D each representsan atom selected from represents an anion; d and q each represents aninteger wherein R and R each represents a group selected from of from 1to 2; n, m and p each represents an integer of 40 the class consistingof alkyl, sulfoalkyl and carboxyalkyl from 1 to 3; L represents amethine group; Z and Z groups having from 1 to 4 carbon atoms, phenyl,sulfoeach represents the nonmetallic atoms required to comphenyl andcarboxyphenyl; R R R and R each repreplete a heterocyclic nucleus havingfrom 5- to 6-atoms sents a group selected from the class consisting ofan in the heterocyclic ring selected from the class consisting alkylgroup containing from 1 to 4 carbon atoms and of a thiazole nucleus, abenzothiazole nucleus, a naphthophenyl; D and D each represents an atomselected from thiazole nucleus, a thianaphtheno- 7',6',4,5 thiazole theclass consisting of oxygen, sulfur and selenium; X nucleus, an oxazolenucleus, a benzoxazole nucleus, a represents an anion; d and q eachrepresents an integer of naphthoxazole nucleus, a selenazole nucleus, abenzofrom 1 to 2; n, m and p each represents an integer of selenazolenucleus, a naphthoselenazole nucleus, a thiazfrom 1 to 3; L represents amethine group; Z and Z oline nucleus, a pyridine nucleus, a quinolinenucleus, an each represents the nonmetallic atoms required tocomisoquinoline nucleus, a 3,3-dialkylindolenine nucleus, an Plete ahetrocyclic nucleus having from 5 t0 6 atoms i id l l 3 b i id l nucleusnd a naphin the heterocyclic ring selected from the class consistingthimidazole nucleus, said process comprising the step of of a thiazolenucleus, a benzothiazole nucleus, a naphthoheating a mixture of a firstcompound having the formula: iaz l nucleus, athiaHaPhth6I10-7',6',4,ithiaZOle I111- cleus, an oxazole nucleus, abenzoxazole nucleus, a naphthoxazole nucleus, a selenazole nucleus, abenzoselenazole nucleus, a naphthoselenazole nucleus, a thiazolinenucleus, a pyridine nucleus, a quinoline nucleus, an isoquinolinenucleus, a 3,3-dialkylindolenine nucleus, an imidazole nucleus, abenzimidazole nucleus and a naphthimidazole nucleus, said processcomprising the step of heating a mixture of a first compound having theformula: wherein R R R Z, d, L, n, D and X are as defined D R previouslywith a second compound selected from those 1; having the formulas: GB llRiN(CH=CH)d-i-O(=LL)n-i=C\ /CCH3 x (a) (H) /ORa BIT R7C-OCH R2 0R9wherein R R R Z, d, L, n, D and X are as defined previously with asecond compound selected from those (b) M0111): having the formulas: (0)CR0 0R8 ll R 0CH=OH-CH R7C-OC wherein R R R Z q, L, p, in, D and X areas defined previously; R R R and R each represents a lower alkyl group;R and R each represents a group selected fromthe class; consisting ofhydrogen, lower alkyl and lower alkoxy; R represents a phenyl group; andR represents a group selected from the class consisting of hydrogen,acetyl, propionyl and benzoyl; said reaction being conducted in anorganic solvent.

3. A process of claim 2 in which the said second compound has theformula:

wherein R and R are each selected from the class consisting of hydrogen,lower alkyl and lower alkoxy.

6. A process for making 3,3'-diethy1-5,5'-di(3-ethyl-2-benzothiazolinylidene)-4,4'-dioxo 1,1 diphenylimidazolinocarbocyanineperchlorate comprising the step of heating a mixture ofS-ethyl-S-(3-ethyl-2-benzothiazolinyl- 14% rate and diethoxymethylacetate in the presence of triethylamine.

7. A process for making 3,3-diethy1-5,5'-di-[(Ii-ethyl-2-benzoxazolinylidene)ethylidene] 4,4 dioxo-l,1'-diidene) 2-methyl-4oxo-1-phenyl-2-imidazolinium perchlophenyl-imidazolinocarbocyanineiodide comprising the step of heating a mixture of3-ethyl-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene]-2-methyl 4oxo-l-phenyl- Z-imidazolinium iodide and diethoxymethyl acetate in thepresence of pyridine.

8. A method for preparing3,3'-diethyl-5,S-di(l-ethylnaphtho[l,2-d]thiazolin 2ylidene-4,4-dioxo-1,1-diphenylimidazolinocarbocyanine perchloratecomprising the step of heating a mixture of 3-ethyl-5-(l-ethylnaphtho[1,2-d]thiazolin-Z-ylidene)-2-methy1-4-oxo 1 phenyl- Z-imidazoliniumperchlorate and diethoxymethyl acetate in the presence of triethylamine.

9. A process for making 3,3'-diethyl-5,5-di-[(3-ethyl-Z-benzothiazolinylidene)ethylidene]-4,4-dioxo- 1,1diphenylimidazolinocarbocyanine iodide comprising the step of heating amixture of 3-ethyl-5-[(3-ethyl-2-benzothiazolinylidene)ethylidene]2-methy1 4 oxo-l-phenyl-Z-irnidazolinum iodide and diethoxymethylacetate in the presence of pyridine.

10. A process for the preparation of1,1',3,3',-tetraethyl-5,5-di[(3-ethyl 2benzothiazolinylidene)ethylidene]-4,4'-dioxoimidazolinocarbocyanineiodide comprising the step of heating a mixture of1,3-diethyl-5-[3-ethyl- 2-benzothiazolinylidene)ethylidene]-4-oxo 2imidazolinium iodide and diethoxymethyl acetate in the presence ofpyridine.

11. A process for making 3,3i'-diethyl-5-[(3-ethy1-2-benzoxazolinylidene)ethylidene] 4,4 dioxo 1,1 diphenyl-5-[ (1,3,3trimethyl-2-indolinylidene) ethylidene] imidazolinocarbocyanine iodidecomprising the step of heating a mixture of 3-ethyl-S-[(3-ethyl-2-benzoxazolinylidene)ethylidene]-2-methyl-4-oxo-1-phenyl 2imidazolinium iodide, acetic anhydride and 2-(2-anilinovinyl)-3- ethyl 4oxo 1 phenyl-S[(1,3,3-trimethyl-2-indolinylidene)ethylidene]-2-imidazolinium iodidedissolved in pyridine.

12. The process of claim 2 in which said second compound has saidformula (e).

References Cited UNITED STATES PATENTS 2,533,206 12/1950 Dent et a1.260-2402 2,537,880 1/1951 Dent et a1. 260-240.1 3,352,680 11/1967 Taberet a1 260-240.2X

JOHN D. RANDOLPH, Primary Examiner US. Cl. X.R.

